Apparatus for grinding wood pulp



Aug. 114, E923, 1,465.6)69

-J. J. WARREN APPARATUS FOR. GRINDING WOOD PULP Filed Aug. '7, 1920 3Sheets-Sheet 1 Aug. M, 21923.

J. J. WARREN APPARATUS FOR GRINDING WOOD PULP 1920 3 Sheets-Sheet 2Filed Aug '7 Aug. 1141 119233.

J J. WARREN APPARATUS FOR GRINDING WOOD PULP Filed Aug. '7, 1920 3Sheets-Sheet 3 wvemcoz W M M w,

Patentwl Aug. M, 3923.

Ldtiddtid earner EDEN J. WARREN, OF BROWNVILLE, NEW YGRK.

APPARATUS FOR GRINDING WOOD P ULIP.

Application filed. August 7, 1920. Serial at. 4.0mm.

To all whom it may concern Be it known that I, Join: J. WARREN, acitizen of the United States, residing at Brownville, in the county ofJefi'erson, State of New York, have invented certain new and usefulImprovements in Apparatus for Grinding Wood Pulp; and Ido hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

This invention relates to the grinding of wood into the so-calledmechanical pulp used in the manufacture of newsprint and other cheappapers. It is the object of the invention to make an improved grinder ofthe magazine type.

In order that the invention may be more clearly understood reference ishad to the accompanying drawings disclosing certain specifiicembodiments thereof, and in which;

Figure 1 is'a transverse vertical section through the grinder, showingthe relation of the magazine, the grindstone and the feeder chains;

Fig. 2 is a vertical section taken along the axis of the grindstone;

Fig. 3 is a sectional detail showing apparatus used to cool the shaft ofthe grindstone;

Fig. 4 is a detail of the same apparatus taken on line H of Fig. 3;

Fig. 5 is a horizontal section on an enlarged scale taken on line 5-5 ofFig. 1, and showing the chains and chain guides of the magazine;

Fig. 6 1s a detail on an enlarged scale taken on line 6-6 of Fig. 5, andshowing the chain mechanism and apparatus used to bend the chain guides;and v Fig. 7 is a further detail of the feeder chain itself.

The magazine grinder shown in Figs. 1 and 2 comprises the ordinarycylindrical grindstone 1 ordinarily electrically driven mounted uponshaft 2 journaled within bearings 3, and enclosed within housing 1.Below this grindstone is an outlet channel 5. The-stone is securelyfixed upon shaft 2 by means of bushings 6 and dished flanges 7 designedto hold the fiindstone in place even though cracked. l ounted upon thegrindstone, and supported by housing 4, is a preferably verticalmagazine 8 terminatin at its upper end in a. hopper 11, into whici i thewood to be ground is fed.

A positive and regulated feed of the w within the magazine 8 is securedby means or two pairs of oppositely positioned endless chains 9, theinner strands or runs of which move downwardly upon two opposite sidesof the magazine. These sides are those which if extended would intersectthe cylindrical face of the grindstone as clearly shown in Fig. 1. Thespecific manner in which these chains are mounted within the side wallsof the magazine will now be described.

' The magazine itself comprises an outer metallic shell or casing 10provided on its interior with a lining of wooden blocks 12, the crosssection of the magazine at-its upper end being slightly greater thanthat at its lower end. Four vertical slots 13 are left in this woodenlining, in which are positioned flexible channel irons 14 which serve asguideways for the inner runs of the feeder chains 9. These channels 14are fixed near the lower end of the magazine, but at their upper endsare held by bolts passing through slots within the channels, thuspermitting free longitudinal movement the necessity for which willappearlater. These channels 14 are tied together at suitable intervals bymeans of transverse tie plates 15 seated within horizontal slots 16within the magazine lining, and normally bearing against the inner faceof the metallic casing 10.

These channels 14 carrying the links of chains 9 are so designed thatthey may be bent inwardly and thus force the chains into closer contactwith the wood within the magazine. This bending or flexing isaccomplished by means of a series of hand wheels 17 situated atintervals aiong the outer sides of the magazine, and shown in detail inFigs. 5 and 6. A series of pairs of horizontal channel irons 18 arefixed upon the outer sides of the casing 10. Upon the outer a naeaoeeflanges of these channel irons and in the planes of the chains arebolted plates 19 within which the hand wheels 17 are threadedly mounted.The inner ends of the threaded shafts 20 of hand wheels 17 are seatedwithin bearing members 22, which in turn bear upon the outer ends ofcompression springs 23. The other ends of these compression springs bearagainst plates 24 riveted to tie plates 15, as shown in Fig. 6, or tothe webs of channels 14- themselves. Apertures 25 are provided withinthe outer casing 10 at these points permitting springs 23 to enter andtransmit pressure to channels 14. By thus flexing these channels theeffective width of the magazine can be varied at will and the pressureof the feed chains against the wood controlled.

Feeder chains 9 are made up of pairs of heavy links 20 tied together bymeans of pins 27. These chains must be of unusually strong construction,as the total pressure which they exert upon the face of the grindstoneamounts to between 45,000 and 60,000 pounds. Fixed on the inner face ofeach link 26, and near the lower or forward end thereof, is a spur orspike 28, the function of which is to bite into the wood and force itdownwardly with the chain. The position of these spikes or spurs is veryimportant. If they were p aced near the upper or rear ends of thedownwardly moving chains they would tear and rip the wood as the chainsmoved away and around their lower sprockets, and this would not onlyincrease the required power, but would shorten the life of the chains.According to this invention, these spurs are fixed to the lower orforward ends of the links. With this structure, as the chain leaves thewood and moves away around the lower sprockets, the link is pivoted atits upper end and the spur is, therefore, withdrawn from the wood in adirection substantially along its length, and is consequently withdrawnas a nail is withdrawn from a board with great ease and no tearing orripping of the wood.

Feeder chains 9 move around fixed lower "sprockets 29 and upper idlersprockets 30.

Power is supplied to these chains from a variable speed motor 32 throughthe intermediary of a reducing worm gearing 33. 34; and 35. The speed ofmotor 32 is controlled by an automatically operated rheostat on thefield coils of the motor. These rheostats may be operated, for example,by a relav controlled by the current consumed by the grindstone, and thespeed of motor 32 and the movement of chains 9 may thus be madedependent upon the power consumption of the grindstone. Anyspeed-regulating means operated by the power consumed by the grindstonewould suffice. There are many such on the market, any one of which couldbe used, and the mechanical details of which form no part of thisinvention. With a fixed, constant feed, the power consumption, whengrinding small or loosely packed logs, would drop far below the minimumrequired for efliciency, while with large, tightly wedged logs thisconsumption would probably rise above 1500 horseower, and burn out thedriving motor. Vith the regulatable feed of the invention, however, thespeed of the feed motor varies with the character of the wood beingground, and maintains the power consump tion of the stone relativelyconstant.

It is common practice to supply the necessary water at the face of thegrindstone with the attendant dangers disclosed above. According to thisinvention the water is introduced at the upper end of the magazinethrough pipe 36. This water is sprayed over the wood in the upper partof the magazine and trickles down through the entire mass of pulpwooduntil it eventually reaches the stone. In so doing it not onlythoroughly saturates this wood and thus softens and prepares it forgrinding, but it itself is thoroughly pre-heated having come intointimate contact with the hot vapors rising from the rinding surfaces.This contact has not only resulted in pre-heating the incoming water,but has condensed the outgoing vapors and thus conserved their heatcontent. The efficiencies gained by this simple expedient of introducingthe water at the upper end of the magazine are as important as the ideais simple. They may be briefly reviewed as follows First, the water ispreheated before coming into contact with the grindstone, and thus thedanger of cracking is minimized; second, the wood is thoroughly softenedbefore grinding and may thus be ground with a minimum of power; and,third, the sensible heat otherwise lost by the passing ofi of the vaporsgenerated by the grinding surfaces is conserved.

lln order to compensate for the inevitable wear of the grindstone, thelower end of the magazine is provided with an adjustable pocket. Thispocket comprises a casting 37 supported upon housing 4 by means ofthreaded bolts 38 passing through apertured lugs 39, integral with thesides of the casting. This casting may be lowered by proper manipulationof nuts 40 to which access may be had by doors 42. In order to present asubstantially continuous wall, the upper edges of the casting 37 and thelower edges of the magazine proper are provided with a. series ofinterfitting fingers 4:3 and 44 respectively. although other means maybe employed.

The frictional heat of grinding is conducted through shaft 2 to bearings3, and often results in melting the bearing metals eeaoeo thereof, asstated above. In order to prevent this and to reduce the temperature ofthe shaft where it is journaled within the bearing metals, a coolingapparatus has been devised according to this invention, and is clearlyshown in Figs. 3 and 4. This apparatus comprises a pair of flangedcollars fixed upon the shaft 2 between the flanges 7 and bearings 3, theupstanding flanges of which are spaced apart to permit the introductionof a cooling fluid between them. Surrounding the shaft at these points,one on each side of the grindstone, but not contacting therewith, aretwo housings 46. In the upper halves of these housings are waterchambers 47, the lower walls of which are provided with a series ofsmall openings 48 through which water plays upon shaft 2 in the spacebetween the collars 45. Water is constantly supplied to these chambers47 through water pipes 49. The" water flows around shaft 2 andinto thelower half of the housing 46, from which it flows away through aperture50. In this manner heat conducted from the grindstone along the shaft isabsorbed bythe water and carried off, and this heat cannot be added tothe normal heat generated within the journal boxes themselves.

The operation of the method and apparatus described above may be brieflyreviewed as follows: Magazine 8 is filled with the ordinary logs whichare to be ground into paper pulp; water is sprayed on these logs throughpipe 36, and feed chains 8 are set in motion. Spurs 9 of these chainsgrip the logs along the entire length of the magazine and force themagainst the rotating grindstone. This force is suflicient to cause theentire column to move slowly into grinding contact with the stone andentirely overcome any tendency of the logs to arch. The grip which thesechains have upon the wood may be illustrated by reversing theirmovement. Upon doing this it has been found that the entire column maybe moved upwardly, none of the central logs dropping out. The fact thatthe lower end of the magazine is slightly smaller than the upper tendsto increase the grip of the chains upon the wood as the latter descendsand is usually sufficient for all pur oses. It sometimes happens.however, w en logs of varying shapes and sizes are being ground thatthey are loosely packed, and hence additional pressure should be broughtto bear upon them to consolidate the column. This may be readilyeffected by screwing inwardly hand wheels 17 which results in bending orflexing the chain guides 14, and pressing the chains even more tightlyagainst the wood. Meanwhile the water through pipe 36 is softening thelogs and becoming pre-heated. As the grindstone wears the pocket at thelower end of the magazine is extended.

\Vith this apparatus it is never possible for the stone to race free ofany load, nor be subjected to greater grinding pressure than it can wellstand, for the variable speed motor 32 controls the rate of feed andmaintains it as nearly uniform as is mechanically possible.

Many of the features of my invention shown and described in thisapplication are not claimed herein, but are being claimed in mycopending application, Serial No. 594,501, filed October 14, 1922, whichis a continuation in part of the present case.

I claim:

1. A wood-pulp grinder of the magazine type comprising the combinationof a grindstone, a magazine'adjacent to the grindstone and adapted toreceive the wood to be ground, endless feed chains operating in themagazine for positively feeding the wood to the grindstone, flexiblechannels or guide ways in the inner walls of the magazine in which thefeed chains move, and means for flexing these channels to vary theeffective width of the magazine.

2. A wood-pulp grinder of the magazine type comprising the combinationof a grindstone, a magazine adjacent the grindstone adapted to receivethe wood to be ground, flexible channels or guide ways in the innerwalls of the magazine in which feed chains move, and means for flexingthese channels to vary the pressure exerted by the chains upon the wood.

' 3. A wood-pulp grinder of the magazine type comprising the combinationof a grindstone, a magazine adjacent thereto adapted to receive the woodto be ground, an adj ustable pocket at the lower end of the magazineadapted to be lowered as the grindstone wears away, downwardly extendingfingers on the'magazine proper. and upwardly extending fingers on theadjustable pocket, the two sets of fingers arranged to interfit and thusmaintain a substantially unbroken wall when the pocket is lowered.

4. A wood-pulp grinder of the magazine type comprising the combinationof a grindstone, :1 magazine adjacent to the grindstone adapted toreceive the wood to be ground, a lining in the magazine, vertical slotsin the lining, flexible channels or guide ways in the slots, endlessfeed chains operating within the magazine for positively feeding thewood to the grindstone and held within the channels or guide ways, andmeans for flexing these channels to vary the pressure exerted by thechains upon the wood.

5. A wood-pulp grinder of the magazine type comprising the combinationof a grindstone. a magazine adjacent to the grindstone adapted toreceive the wood to be ground, endless feed chains operating within themagazine for positively feeding the wood to the grindstone, and meansfor varying the efiective width of the magazine to conjustable pocket atthe lower end of the megatrol the pressure of the feed chains againstzine adapted to be lowered as the grindstone the wood. wears away, thecorresponding inner faces 10 6. A wood-pulp grinder of the magazine ofthe magazine and pocket being substan- 5 type comprising the combinationof a rindtia-lly in the same plane. stone, a magazine adjacent thereto aapted In testimony whereof I afiix my signature.

to receive the wood to be ground, and an ad- JOHN J. WARREN.

